Fire protection systems utilize fire fighting/protection instruments such as, for example, sprinklers and/or spray nozzles that are activated to distribute fire-extinguishing fluid, preferably water, in the room or building. For some sprinklers, fluid discharge is controlled by a trigger assembly. These trigger assemblies support in place a closure member at the discharge outlet of the sprinkler or other instrument. The trigger can be controlled or automatically operated to displace the closure member thus allowing firefighting fluid such as water to discharge from the outlet of the instrument. One type of trigger assembly is a fusible link as provided in an automatic sprinkler. The fusible link includes a link member having two halves in which a solder element holds the halves in place to support the closure member at the sprinkler outlet. The solder member is thermally rated to melt at a threshold temperature thus, allowing the halves to separate and displace the closure member for sprinkler operation. Another type of trigger assembly includes a bulb type trigger assembly provided in an automatic spray nozzle or automatic sprinkler. The bulb type trigger assembly includes a fluid contained within a glass bulb that supports the closure assembly at the sprinkler outlet. The fluid expands upon exposure to heat and at a sufficiently high temperature, the fluid can expand so as to shatter the glass bulb. Once the bulb shatters, the closure member can be displaced to allow for fluid discharge from the sprinkler outlet.
The trigger assemblies for automatic sprinklers and spray nozzles are generally fragile and can be subject to damage during shipping, storage and/or installation. For example, the trigger assembly in a sprinkler mounted to a branch pipe of a sprinkler system can be damaged by building materials such as, for example, dry wall, pipe or other obstructions that are moved about during construction. In addition, the trigger assemblies can be damaged when mishandled or dropped by an installer. When the trigger assembly is damaged, the entire sprinkler or nozzle generally must either be discarded and/or replaced which can be a significant cost to the manufacturer, supplier, installer and/or building owner.
To protect the trigger assembly during shipping and/or installation a cover or protection device can be disposed about the sprinkler such that the trigger assembly is shielded from damage. One known protector is shown and described in U.S. Pat. No. 6,669,111 which is directed to a protector for a thermally responsive member of a sprinkler head. Shown is a protector that pivots or separates about a hinge to envelop the frame arms of the sprinkler. Another protector is shown in Design Pat. No. D498,818 and is more specifically directed to a bulb cover. Another known protection device is shown in U.S. Pat. No. 7,757,967.
PCT Patent Application Publication No. WO 2015/191619 discloses another trigger assembly for a fire protection sprinkler that cannot be sufficiently protected by these prior art cover devices. More specifically, WO 2015/191619 discloses a trigger assembly with a hook and a strut arrangement held together by a link with a designed fracture region. The sprinkler is actuated by an electrically operated linear actuator that breaks the link along the fracture region to uncouple the hook and strut. WO 2015/191619 shows the linear actuator extending radially from the sprinkler over a radial distance that cannot be sufficiently protected by the prior art cover devices. Accordingly, the capacity of these known protective devices is limited.